Generally, electricity is supplied to home appliances from a power plant operated by a public or private company, through a power transmission line, and a power distribution line.
That is, power is supplied not by a distributed structure but by a centralized structure. In other words, power is supplied through a radial structure expanding from the center to the periphery. This is not a customer-centered structure but a supplier-centered one-way structure.
Therefore, residential customers can get only limited information about prices of electricity from a power exchange.
Furthermore, since electricity prices are practically fixed, it is difficult for customers to buy electricity at desired prices.
Thus, much research is being performed on smart grids to solve the above-mentioned problems and use energy efficiently.
A smart grid is a next-generation power and management system developed by applying information technology (IT) to the existing power grid for improving energy efficiency by realizing two-way and real-time information exchange between power providers and consumers.
In addition to unilateral power supply from a power supply source to a network to which home appliances are connected, two-way communication is necessary between the power supply source and the network to realize a smart grid for residential customers.
However, in a case where the two-way communication is performed, external factors may intrude into a communication path to cause a failure of network for power supply.